A wide variety of tools are used in the oil and gas industry for forming wellbores, completing drilled wellbores, and producing hydrocarbons from completed wellbores. Examples of wellbore-forming tools include cutting tools, such as drill bits, mills, and borehole reamers. Drill bits and other tools may be formed from metal matrix composites (MMCs), and may be referred to herein as “MMC tools.”
An MMC tool is typically manufactured by depositing matrix reinforcement material into a mold cavity designed to form various external and internal features of the MMC tool. Interior surfaces of the mold cavity may be shaped to form desired external features of the MMC tool. Temporary displacement materials, such as consolidated sand or graphite, may be positioned within interior portions of the mold cavity to form various internal (or external) features of the MMC tool. A binder material may be added to the mold cavity, and the mold may be placed within a furnace to liquefy the binder material and thereby allow the binder material to infiltrate the reinforcing particles of the matrix reinforcement material.
MMC tools may be erosion-resistant and exhibit high impact strength. However, depending on the particular materials used, MMC materials can also be brittle and, as a result, stress cracks can occur as a result of thermal stress experienced during manufacturing or operation, or as a result of mechanical stress experienced during use.